Dear Editor,
I have read with keen interest the article, “Music and oral premedication for pain management during outpatient hysteroscopy: results from a randomised controlled trial” written by Alessandro Loddo et al.1 This study addresses the clinically significant issue of pain associated with outpatient hysteroscopy and compares the effects of music and oral premedication for its management. The authors have done a great job in describing the strengths and limitations of their study. However, I would like to draw their attention to an important methodological consideration that might be helpful in the interpretation of their results. The authors state that those patients whose hysteroscopy could not be completed because of severe pain due to cervical stenosis requiring mechanical dilatation under general anesthesia were excluded from statistical analysis. As the main objective of the study was to evaluate the efficacy of strategies for pain management during hysteroscopy, I wonder whether exclusion of these participants might have influenced the analysis of interventions. One previous methodological research study has suggested that the treatment effects might be influenced by the exclusion of randomised participants from analysis and can introduce bias in randomised controlled trials.2 Therefore, it would be valuable to report the number of failed procedures in each randomised group and clarify whether their exclusion had any potential impact on the observed treatment effects. Considering procedural failure alongside pain scores in an appropriate analysis may also provide a more comprehensive assessment of the clinical effectiveness of music and oral analgesia.
